expected primary-expression before const什么错啊解决思路

expected primary-expression before const什么错啊!C/C++ code#include string#include vector#inclu

expected primary-expression before const什么错啊!

C/C++ code
#include <string>#include <vector>#include <iterator>#include <iostream>int main(){    const vector<string>::size_type st=10;    vector<string>  vs(st,"xx");    return 0;}

就这样很短的一段代码,怎么还报错啊!

[解决办法]
main之前添加using namespace std;